Showing papers on "Data acquisition published in 1976"

Seismic data telemetering system

Abstract: A plurality of data acquisition and transceiver units are connected in series to a central signal processor through a common telemeter link. The telemeter link includes a data channel, an interrogation channel and a control channel. The signal propagation velocity through the control channel may, for example, be greater than the signal propagation velocity through the interrogation channel. The central signal processor sends an interrogation signal through the interrogation channel to the data acquisition units. After a selected delay, a control pulse is transmitted. The delay between transmissions of the two signals is proportional to the differential travel time of the signals in the two channels. Accordingly the signal through the control channel will overtake and intercept the signal propagating through the interrogation channel, at a selected data acquisition unit. When any selected data acquisition unit receives a control signal through the control channel at the same time that it receives an interrogation signal through the interrogation channel, that unit is activated and a desired function is performed. The control signal is a square wave pulse having a width which is adjustable by integral multiples of the differential travel time. By adjusting the width and transmission-time delay of the control pulse, any selected subset of one or more consecutive units may be activated. Each data acquisition unit may have two or more input channels, which are connected in turn through common electronics to the data transmission channel by means of a channel selector or multiplexer. The interrogation signal may exist in one of two or more states. In the first state, in combination with a control pulse, the interrogation signal resets the multiplexer. In the second state, the interrogation signal advances the multiplexer to the next input channel in sequence.

Practical aspects of a maximum likelihood estimation method to extract stability and control derivatives from flight data

Abstract: A maximum likelihood estimation method was applied to flight data and procedures to facilitate the routine analysis of a large amount of flight data were described. Techniques that can be used to obtain stability and control derivatives from aircraft maneuvers that are less than ideal for this purpose are described. The techniques involve detecting and correcting the effects of dependent or nearly dependent variables, structural vibration, data drift, inadequate instrumentation, and difficulties with the data acquisition system and the mathematical model. The use of uncertainty levels and multiple maneuver analysis also proved to be useful in improving the quality of the estimated coefficients. The procedures used for editing the data and for overall analysis are also discussed.

Digital Representation of Three-Dimensional Surfaces by Triangulated Irregular Networks (TIN). REVISED.

Abstract: : A Geographic Data Structure is developed which permits the digital acquisition, storage and application of data sets of three or more dimensions, in particular topographic terrains. The Structure consists of a Triangulated Irregular Network and higher-level structures. Comparisons with systems based on regular grids reveal that the Geographic Data Structure is advantageous in terms of storage space needed, computer time, and accuracy, in the acquisition, storage and application of digital terrain.

X-ray data acquisition system and method for calibration

Abstract: A tomographic x-ray imaging system comprises a large plurality of parallel data acquisition channels which integrate and digitize signals from an array of x-ray detectors. Calibration pulses are injected into each data acquisition channel to permit measurement of drift in electronic gain and dc offset parameters. Separate x-ray detectors continuously monitor the intensity of the x-ray source. The measured values for channel gains, dc offsets, and source intensity are fed to a digital computer where they are automatically combined with x-ray transmission data to compensate for system drift and extend the period between calibration measurements.

The theory and applications of ocean wave measuring systems at and below the sea surface, on the land, from aircraft, and from spacecraft

Abstract: Methods for measuring and analyzing ocean waves are described, including those presently in use on spacecraft and planned for SEASAT-A. Potential difficulties with synthetic aperture systems for a spacecraft are described and an alternate design is suggested. The different methods can yield different kinds of spectra and other kinds of imagery. Ways to compare different kinds of data are given. The scientific and practical applications of data from spacecraft are given.

Some Problems in Diesel Engine Research with Special Reference to Computer Control and Data Acquisition

Abstract: SYNOPSIS A versatile computer-based testing and data acquisition facility developed to improve the speed and accuracy of engine research work is described. The role of computer-aided technology is illustrated through the discussion of two quite separate problems.Fuel burning rates (heat release diagrams) are the most basic measurement of combustion, yet highly sophisticated equipment and techniques are required to obtain accurate rate diagrams. The problem is illustrated through the derivation of heat release data by analysis of averaged and smoothed cylinder pressure diagrams from naturally aspirated and turbocharged diesel engines. Techniques developed for transducer mounting, choice of sampling interval, data-logging, processing, smoothing, etc. are presented.During transient conditions (e.g. sudden load chnages) a turbocharged diesel engine moves through operating regimes not normally encountered in steady state operation. Although empirical models have been used to prodict the transient response of t...

Acoustic data acquisition system

Abstract: A data acquisition system is provided for acquiring acoustic information from an array placed in a body of water and for transmitting the information through a single transmission line to remotely located data processing equipment. The array includes a plurality of sensors, a plurality of sub-multiplexers, a master multiplexer and an A/D converter. The sensors are arranged to receive acoustic signals from objects submerged in the water and each sensor provides an analog electrical signal representative of the acoustic signal received thereby. Each sub-multiplexer has a plurality of inputs and a single output with each of the inputs being connected to a corresponding one of the sensors. The sub-multiplexers sequentially sample signals received at their inputs from the sensors connected thereto and transmit these samples to a single output provided on each sub-multiplexer. The master multiplexer sequentially samples signals from the outputs of the sub-multiplexers and transmits these samples to the A/D converter. Multiplexer timing is controlled so that the A/D converter repeatedly receives analog samples from all acoustic sensors. The master multiplexer may further include two individual multiplexers and means for alternately connecting outputs of these multiplexers to the master multiplexer output. The A/D converter encodes each sample into a binary data word. These binary words are changed to a ternary code by a ternary encoder and then transmitted through the single transmission line to the data processing equipment.

Analytical instrument optimum data acquisition method and apparatus

Abstract: An analytical instrument employing ensemble averaging to improve the signal-to-noise ratio including means for determining the most efficient scaling factor and for controlling the instrument to maintain assurance of efficient averaging.

A Computer Controlled Raman Spectrometer System

Abstract: We describe a software system and a hardware interface between a laser Raman spectrometer and a time-shared computer. This data acquisition system controls the wavelength drive of the spectrometer and the analyzer orientation using stepping motors and position sensors. With this method accurate depolarization ratios can be determined at every wavelength increment. Digitized photon counting gives good signal/noise ratios and a wide dynamic range for Raman intensity measurements. The software design permits automatic separation of isotropic and anisotropic spectra, repetitive counting periods, instant scope display of raw, reduced or integrated data, and numerous data refinement options.

High sweep rate waveform display control for digital recording waveform devices

Abstract: A digital waveform measuring and display oscilloscope includes a digital memory which stores one full screen of waveform data. The analog waveform is sampled, digitized and placed in memory at a user selected mode and sampling rate. A data acquisition mode control permits the user to select a continuous mode in which a live waveform is displayed moving from the right to the left on the screen. A hold mode is provided in which a preceding full screen data array is captured in the memory and displayed as a static display. A trigger mode is also provided with a variable delay, related to multiples of a full screen array, in which one full screen array is captured in relation to a trigger event and displayed as a static display. A particularly unique Periodic Hold mode creates a cyclical sequence which includes data acquisition and simultaneous display blanking which is terminated in response to a trigger signal sequence. The captured data is displayed for a short time and is followed by an automatic signal to the control system to again initiate acquisition of the waveform signal in a free running mode. As data is acquired, the trigger circuit is automatically enabled to again stop the data acquisition at or following a trigger signal. The display is blanked during each data acquisition with the previous image momentarily retained on the display screen during the blanking period. The display is a series of static displays which appear to the user essentially in the form obtained with a conventional oscilloscope.

Acoustic data acquisition device

Abstract: Acoustic signals are received, selectively filtered, and digitally processed, e.g., by digitizing an amplitude, the peak of an echo, or the transit time, and the digital data are stored in a memory whose storage cells are associated with particular frequencies. Other acoustical signals are similarly processed but compared with the reference data to obtain a spectral representation of differences or ratios.

The use of a high sensitivity ultrasonic current meter in an oceanographic data acquisition system

Abstract: The paper describes the design of a high performance two-axis ultrasonic current meter and how this sensor has been designed into a general oceanographic data acquisition system with additional sensors for pressure, temperature, salinity, sound velocity and current direction.

Data acquisition and transfer system

Abstract: A self-clocking binary data acquisition and transfer system in which each t of any data stream is divided into four time periods such that both 0 and 1 data bits are high during the first time period and a 0 will go low after the first time period and a 1 will be low after the third time period. The first, second and third time periods are used for transmission of information and the fourth for initialization.

A Controllable Real-Time Data Collection System for Coastal Oceanography

Abstract: A controllable real-time data acquisition and monitoring system was developed for coastal oceanographic parameter measurements. This system continuously measures profiles of temperature, conductivity, current velocity and direction as a function of depth at a number of fixed off-shore locations. The data acquisition, monitoring and control system features make this system generally suitable for unattended area monitoring applications in environmental sciences. The system has been in routine operation since July 1975.

Distributed Computer Intelligence for Data Acquisition and Control

Abstract: The critical needs of nuclear science have motivated a trend toward distributed computer systems for data acquisition and control. Such systems combine the flexibility of distributed input/output systems with the capability of handling high data rates and critical control loops by localized intelligence and data reduction. Common problems of such systems such as data rate variations, analysis of alternative configurations, and utilization of standard modules are discussed. Emphasis is placed on the role of the microprocessor as a common component of the system.

A digital elevation data collection system

Abstract: Most stereoplotter systems currently in use were designed primarily for producing contouring and profiling outputs on a coordinatograph Recently, however, there has been an increasing need for topographic information in the form of digital grid-point elevation data Whereas some existing systems can be used to extract this type of data, they cannot do it rapidly or efficiently The AS-11B-X system is an experimental model of a new type of system intended explicitly for the collection of digital elevation data The system was developed for Rome Air Development Center by Bendix Research Laboratories The system achieves an increase in data collection rates of from 10-50 times that presently being obtained with conventional system at no decrease in accuracy The AS-11B-X system obtains its high data-collection in parallel using digital processing A combination of special techniques is used to simplify the digital processing and to reduce the amount of data storage required

A microprocessor oriented data acquisition and control system for power system control

Abstract: The advent of microcomputer systems with their inherent cost/performance advantages had precipitated a reassessment of known application areas that heretofore were not considered candidates for digital systems solution. Described in this paper is a MICRO processor oriented Data Acquisition and Control system referred to as MICRODAC which is capable of monitoring high voltage perturbations (via transducers), accepting and issuing control commands, performing format changes and error encoding/decoding, performing system self checks, and transmitting data to supervisory computers. This system performs a very necessary function in power system data acquisition and control at low cost, high reliability, and low power consumptions.

Hybrid holographic non-destructive test system

Abstract: An automatic hybrid holograhic non-destructive testing (HNDT) method and system capable of detecting flaws or debonds contained within certain materials. This system incorporates the techniques of optical holography, acoustical/optical holography and holographic correlation in determining the structural integrity of a test object. An automatic processing system including a detector and automatic data processor is used in conjunction with the three holographic techniques for correlating and interpreting the information supplied by the non-destructive systems. The automatic system also includes a sensor which directly translates an optical data format produced by the holographic techniques into electrical signals and then transmits this information to a digital computer for indicating the structural properties of the test object. The computer interprets the data gathered and determining whether further testing is necessary, as well as the format of this new testing procedure.

A Controllable Automated Environmental Data Acquisition and Monitoring System

Abstract: A real-time data acquisition and monitoring system was developed for coastal oceanographic parameter measurements. This system continuously measures profiles of temperature, conductivity, current velocity and direction as a function of depth at a number of fixed off-shore locations. The data acquisition, monitoring and control system features make this system generally suitable for unattended area monitoring applications.

A Computer Based System for Data Acquisition and Control of Scientific Experiments on Remote Platforms

Abstract: The observation and measurement of environmental processes is made simple and economical using a minicomputer based system which controls activities and logs data from a remote unattended platform by 20 000 baud, digital, cable telemetry. The remote station electronics is bus oriented and provides A/D and D/A conversion, logical input/output and servo motor control. The minicomputer, an Interdata 74 with only 16K-byte core, houses a novel, real time, multi-tasking operating system featuring an interpretive language called REMCODE. One version of this system operates a submersible water quality analyzer which connects, via the dialed telephone network, to a central computer for real time data retrieval and remote reprogramming. Another version samples 48 analog plus 6 digital inputs at rates up to 20 Hz, from a tower in Lake Ontario and logs them onto computer-compatible magnetic tape.

Computer-controlled Auger spectrometer

Abstract: The present paper describes the system configuration of a computerized Auger electron spectrometer, which incorporates various schemes of complicated process control as well as automatic data acquisition, reduction, and retrieval. Central to the system is a sensor‐based computer which controls the spectrometer and interfaces with a host computer where large‐scale computations can be performed. With a graphic terminal as its operator’s station, the system can operate in either automatic or interactive modes. Examples of the process control implemented for the system are given, accompanied by the circuit adaptations necessary for hardware interfacing. Spectral data obtained by the system indicate that the rate of data acquisition has increased by two orders of magnitude with a signal reproducibility of better than 0.5%. Experiments with controlled surface contamination suggest that the spectrometer sensitivity can be doubled by time averaging a number of spectra measured under identical conditions.

A Software System for Data Acquisition in Nuclear Physics Experiments Using CAMAC

Abstract: An event-oriented, modular software system for data acquisition in nuclear physics experiments has been implemented on PDP-11 computers under the RSX-11D operating system. The system is designed to support high-speed data acquisition in a broad variety of nuclear physics experiments having multiple event types and using CAMAC instrumentation as the experimental interface. The system provides a simple, problem-oriented language for the specification of CAMAC operations to acquire data from each class of event. It provides automatic bufferinq of experimental data from the CAMAC hardware and recording on magnetic tape. Certain common utility functions are provided, especially histogram entries and plotting on on-line displays, along with associated operator control functions. The experimenter specializes the system to his needs by writing FORTRAN subroutines which specify necessary on-line analysis of data and control histogram entry. The software depends on a special event-trigger module which was designed in conjunction with the software and is used to identify the various different classes of events, to facilitate manual control and testing of an experiment, and to facilitate comnmunication between different software modules in the system.

Chapter 5 – Applications

Abstract: Publisher Summary This chapter focuses on the applications of minicomputers. The range of applications of minicomputers is wider than that of standard computers, which are not designed with a view to the interfaces necessary for process control and data logging. For certain applications, minicomputers are primarily chosen because of their small size. Considerable management participation is essential when a minicomputer is introduced for process control. The simplest application of a computer for actual control of a process, in contrast with the acquisition, reduction and display of data, is sequence control of a noncontinuous batch-type process where signals are transmitted to actuators, such as valves, motors and relays. A minicomputer configuration for direct digital control can need a larger memory than the systems used for mere data acquisition and reduction. The minicomputer provides an economic method for laboratory instrument control and computation especially as software systems are capable of real-time operation with many levels of interrupt while disc storage devices are available for most minicomputers. A minicomputer can be programmed to control and monitor a large variety of instruments, reduce the data obtained from them, perform appropriate computations upon this data and produce a meaningful report of the experiments. The real-time software enables the minicomputer to attend to several laboratory instruments at the same time.